/Engine/Plugins/Runtime/GameplayAbilities/Source/GameplayAbilities/Public/AbilitySystemBlueprintLibrary.h
Returns true if the attribute actually exists
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(BlueprintPure, Category="Ability|Attribute") static bool IsValid ( [FGameplayAttribute](API\Plugins\GameplayAbilities\FGameplayAttribute) Attribute )